Conserve Critical Habitat in the Face of Climate Change in Midwestern Lakes by Managing Watershed Land Use

MINNEAPOLIS/ST. PAUL (7/27/2022) – Lakes in the Midwest are losing their cold, oxygenated habitat due to climate change and nutrient pollution. This loss of critical habitat has negative consequences for water quality, fish and the production of greenhouse gases. While data shows that effective watershed land use management at the local scale can protect cold water, oxygen-rich habitats and reduce nutrient pollution in Midwestern lakes, the goals specific lakes for watershed management are lacking.

In a study from the University of Minnesota published in Ecosphere, researchers used statistical models to estimate the resilience of more than 10,000 Upper Midwest lakes to climate change and land use to identify the temperature and watershed conditions above which the critical habitat has been lost. For lakes in which watershed land use was expected to influence cold-water habitat, researchers identified lake-specific thresholds for protecting or restoring forested watersheds. They also estimated uncertainty about how individual lakes would respond to changes in climate and land use.

“Sometimes we can feel hopeless thinking about the negative consequences of climate change. This research is an example of how we can manage local conditions to slow or mitigate these negative effects,” said Gretchen Hansen, Ph.D., the study’s principal investigator and assistant professor in the College of Food at U of M, Agriculture and Natural Resource Sciences (CFANS) Department of Fisheries, Wildlife and Conservation Biology.

The researchers found:

  • Under climatic conditions from 2040 to 2059, the number of lakes with suitable cold-water habitat is expected to decrease by 67%, while the number of lakes with unsuitable habitat is expected to increase by more than 200%.
  • Changes in land use in watersheds were predicted to affect the availability of suitable, oxygenated cold-water habitats in 24% of the lakes. These are high priority lakes in terms of protecting or restoring forested watersheds.
  • The lakes varied in the amount of temperature increase they could withstand without affecting their resistance to climate-influenced habitat change. The median climatic resistance was 4.3 degrees Celsius, with some lakes able to maintain cold-water habitats even with temperature increases of up to 14 degrees Celsius.

This research builds on decades of work by the Minnesota DNR and its partner agencies, which resulted in the protection of forested watersheds for critical climate refuge lakes in the state. Currently, the State of Minnesota uses a 75% forested watershed protection threshold to protect overall water quality, which also protects the resilience of cold-water habitat in these lakes. This research identifies more variable lake-specific protection targets that could potentially explicitly inform future cold-water habitat conservation efforts.

“Our research identifies the variability in levels of watershed protection needed to maintain cold-water habitat,” Hansen said. “Some lakes need more protection, others can get by with less. This work also extends the approach to lakes outside of Minnesota to enable regional coordination of habitat management in the face of climate change.

Additionally, resource management agencies in other Midwestern states are interested in implementing programs similar to those in Minnesota based on the results of this research.

“Michigan DNR is developing a plan to improve water quality and reduce cisco population declines in the state’s inland lakes,” said Joe Nohner, Midwest Glacial Lakes Partnership Michigan Department of Natural Resources coordinator and biologist. “The results of this study will help us prioritize and determine which lakes offer the best response to conservation efforts.”

These efforts include potential changes in the management of state forests, the implementation of grants to plant trees on a large scale on public and private lands, and collaboration with land conservation and conservation partners.

According to Hansen, their research on landscape patterns can help prioritize conservation at multiple scales.

“We hope our results will help local and regional groups identify management targets for the protection of critical habitat in vulnerable lakes.” Although there is uncertainty associated with such models – as individual lakes vary in their responses due to water residence time, food web dynamics, fisheries management and other factors – more detailed information about lake-specific responses and characteristics can help explain why an individual lake may react differently than expected,” she said. “What we’ve learned will help us tailor appropriate management actions at the scale of each lake, and despite current limitations, we believe our landscape-level approach is an essential step towards conserving freshwater resources. in Midwestern lakes using the best available science.”

This study was funded by the United States Fish and Wildlife Service and the Midwest Glacial Lakes Partnership.

Learn more about preserving Professor Hansen’s cold-water habitat in this short video.

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About the College of Food, Agriculture and Natural Resource Sciences
The College of Food, Agriculture and Natural Resource Sciences at the University of Minnesota (CFANS) strives to inspire minds, nurture people and sustainably improve the natural environment. CFANS has a heritage of innovation, bringing discoveries to life through science and educating the next generation of leaders. Every day, students, professors and researchers use science to meet the great challenges of today’s and tomorrow’s world. CFANS offers an unparalleled breadth of experiential learning opportunities for students and the community, with 12 academic departments, 10 research and outreach centers across the state, Minnesota Landscape Arboretum, Bell Museum of Natural History and dozens of interdisciplinary centers.

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